DESCRIPTION: (Modified from Abstract) The powerful mineralocorticoid 19- nordoxycorticosterone (19-nor-DOC) is excreted in greater quantities in the Dahl salt sensitive-hypertensive (SS/Jr) rat than in the Dahl salt- resistant (SR/Jr) rat, but no genetic studies to indicate co-segregation with blood pressure have been performed. The investigators present data that the enzymes responsible for the synthesis of the precursors of 19- nor-DOC is not the 11-beta-hydroxylase, as has been previously assumed, and therefore are describing methods by which applicants plan to study the synthesis of these potentially important steroids. The investigators propose to measure adrenal production of corticosterone, 18-OH-DOC, 18-OH-corticosterone, 19-OH-DOC and 19-OH-oic- DOC (precursor of 19-nor-DOC) in control and stimulated zona fasciculata cells from Dahl SS/Jr, SR/Jr, and inbred Lewis rats, which are genetically distant from the Sprague-Dawley from which the Dahl rats derived. They will compare this production of steroids with the strain- specific isolated mitochondrial conversion of DOC to the above steroids. They also propose to do breeding studies and generate F1, F2 and backcross generations between SS/Jr to SR/Jr and SS/Jr and Lewis rats to compare the genotype for the 11-beta-hydroxylases with the mitochondrial conversion of DOC to the above steroids, the synthesis of steroids by isolated cells under basal and stimulated conditions of individual adrenals, and the urinary excretion of 19-nor-DOC collected under stable conditions. They will also attempt to clone the enzyme responsible for the biosynthesis of 18-OH-B in the zona fasciculata with an adrenal library.